import numpy as np
a = np.array([1, 2, 3, 4])
b = np.array([5, 6, 7, 8])


r=np.sin((a*b)/(a+b))
print("sin[(a*b)/(a+b)]:", r)

# Output:
# sin[(a*b)/(a+b)]: [0.74017685 0.99749499 0.86320937 0.45727263]